Outlet-box for electric conduits.



W. A. BONNELL. OUTLET 130): FOR ELECTRIC GONDUITS.

APPLICATION FILED AUG. 1, '1908.

Patented May 11, 1909.

81 W00 wtoz zwvu L n citizen of the 1 employed in connection with mill or 0th WILLIAM A. B0 HELL, OF Ni tom-em: Be it known a Winnin A. lfioztimant, :ecl States, l'bSiflig in the city, county. nl State of New York, haw invented certain new and useful lnipi'meiiieiits in iliutlet 30 s for Eleotrio Conduits, of which the following is it full, clean, and exact (lkSCliPtlOXl.

iii invention relates to iniln'ovenients in outlet boxes for electric contlnits untl has to" its object the provision of simple and attentive means for holding the conduits in position in the box in such manner that the greatest (lumping otll'eot' may he seemed Withmit thin of nhracling the insulation on the continits.

A further object is to provide inenns'for holding S0-Cfilll lniock-ont disks in position in ;i'l'.,.COl1(.llllt receiving sockets oiapertures in the box when the sanio'ure not in use.

With these and other objects in View the invention con ts in the o0 ion and arrangement of parts illust 'nteil ill the acoompa-nying ("twining in which Figure l is a plan view of a ceiling outlot nor: looking at the top when in pos tion. i 2 is a sectional View throngl'i one of the conduit sovkets showing at conduit clump in pos tion. Fig. 3 is {L View similar to 1* 2, showing a knock-ontdisl; held in. place in u conduit socket by the clamping moans. Fig. 4- comprises plnnnnd edge. \i8WS my improved damping; plate. i prises plan and edge. views of the knmzlyout dis a.

In the embodiment of my invention herein selected for illustration, 1 have chosen to show my improved clamping means in (onneotion with a ceiling outlet box, although it is obvious that the sumo menus nuiy ho Fign 5 a junotion boxes for electrical oontlui n the form have shown, the box consists of n oylindyicnl body portion 1, which is provided at its center Withn lead 2 for a gaspipe, to 'whivh tho box may be secured in any suitable inanner, us by clamping screws (not shown). Around the perimeter of the hase of the box are 211' winged: n plurality of conduit bushings S, which may be cast integral with the base i of the box, as shown. Each of these bushings is provided at its lower extremity with n flange forming a shoulder upon Whioh the end of the in Solution 6 oi the While the ti fie caihles T p in opening 1 the bnslinn nrtiierniore, plfivltlfii v a caning, tho cmuluits within the hon it nti inst liilin'lltlllCfi that 'hei ho so securely held get 01" their at the sumo t. olznnpin not :iln'u le or in any eoinluit insulation. :1. nionns for hoidi (luits in position i of clamping; lllflb. similar shapetl (lo n exterior of the tom: 0 box. iiuoh ("tannin in Fig. 4- is ii-{nit your tn 1].. Whi .:i elei rear face 12 of the olzin'ipii'ig platei (luit when the plate g'ng oosn niesns Toenails in'g plans is aperture i l to re saio soiwv bolt-mu of the. pinto-receiving: clepi'ession It is slotted, as at l5. to permit the fol-mm and lLKClGViUTl (lumping: nnC. role-ass movements of said ohnnning pl ins; plate mm in Gi li? that ti o ol-znnp with the least iction upon oi? tho Plfiiii'd'fi'o and for gnicln .("e of at the T8211 End 0;" the g 16 which SlltlEra' in "1. groove 17 formed in the 12 of the (3V ion. it). I enien il 11. oi the ol wining; iii; on either side o so formed as not to hear on f ne cori' yntling 'illi sui' faces of the Wall 12 01' moans the clamping;

plate moves easily to clamping position,

,u'ithout undue friction between its bev will and the beveled will of the plate-Le ceiving depression.

The form ofcontluits commonly used oonsists, is hei'e shown, a s 'iii'zilly wound,

ei'ingsti'ip'of soft inetzih the strip form co; ing the om'ering being mine 0i 1 convex-ed on the outside, thus torniingz e. spun! the plate-receiving the disk.

.the more securely hold the conduit against being pulled out of its bushing or displaced. 'lhe clamping face 21 of the plate 9 is turthermore provided with holding ridges or teeth 23, Fig. 4, to more securely engage the conduit and prevent rotation thereof in its receiving bushing.

Referring now to Figs. 3 and 5. it will be seen that the construction and. arrangen'ientof clamping plate here illustrated affords means for holding a socalled knock-out disk 24 in such of the conduit receiving bushings 3 as are not in use. The inner walls of said bushings are somewhattapered, as shown at Fig. 23, and the knock-out disks are provided with permit said disks to be inserted for a short distance within the bushings to a depth substantiallyflush with the bottom of the clamping plate-receiving depression -l0. \Vhen in such position, the clamping plate when screwed home will project over the edge of the disk and serve to hold it in place. While the taperingof the inner wall of the bushing and the beveling of the perimeters of the disks is sutiicient under ordinary conditions to hold the disks in proper' position within the sockets, I provide additional means on the disk to be engaged by the clamping plate, in the form of :1 lug 27, which may, rest .upon the bottom of the clamping plate depression 10, and which is engaged by the clamping plate.

WVhen the outlet box is in position and it is desired to insert one or more conduit-s therein, the knock-out disks 24 may be knocked out of position by means of a screwdriver or other instrument, by a sharp blow thereon from the under side, the projection of the clamping plate over said disk being insufiicient to prevent this'operatiou, and the lug 27 upon the disk (when said lug is provided) is of such thickness as to be easily broken by the knock out blow upon The clamping plate screw 13 is then loosened, thus permitting the clamping plate to be moved back from its projection over the bushing, the conduit is in serted, and the clamping plate again screwed home until its forward or clamping edge firmly engages the same. I

By the above coustruction'it will be noticed that the interior of the outlet box is left substantially nt-irely free for the mabeveled perimeters 20, which uipula-tion and positioning of the electric cables, inasmuch as the clamping plates are located upon the upper or exterior surface of the base, and the conduit receiving bushings 3 project but a comparatively short distance within the box. The advantage derived from this open or unobstructed construction of the interior of the box will be appreciated by those skilled in the art.

A further and very important advantage of arranging the clamping plates upon the rear of the base of the box is, secured for the following reasons. The electricians, in cutting and fitting the conduits, rarely cut them off square but almost invariably cut them on an angle, and furthermore unless unusual care is exercised an uneven jagged end is left on the conduit. It is essential therefore to the secure holding of the conduit in the box that'it be clamped or gripped not immediately at. the end but at a considerable distance therefrom. By locating the clamping plates upon the rear of the base, it is possible to grip the conduits. at the greatest distance from their ends consistent with practical arrangement of the clamping means.

While I have here illustrated and described a particular construction and arrangement of outlet box, it is obvious that the same may be varied in detail without departing from the spirit and scope of my inventio \Vhat I claim is: 1

1. An outlet box having a plurality of conduit receiving bushings, depressions in the exterior of the rear of said box adjacent said bushings, clamping plates arranged in said depressions, said plates and depressions having coiiperating cam faces at their rear ends, there being slots in the bases of said depressions and clamping screws extending through said slotsand engaging saidplates and operable from the inside of said box to move said plates to clamping position.

2. An outlet box having one or more conduit receiving bushings fixed to its base and conduit clamping means arranged at the rear of the base of said box, constructed and arranged to engage the conduits at points'dis-z tant from the ends of said conduits.

3. An outlet box having one or more stationary conduit receiving bushings fixed to n its base and conduit clamping plates located at the rear of the base and constructed and arranged to, engage the conduits at points substantially in the plane of the base.

4. An outlet box having one or more stationary conduit receiving bushings proj'ecting into said box and clamping means on said box constructed and arranged to engage the conduits substantially at the base of said bushings.

Au outlet box having one or more conduit receiving bushings projecting into said ljox, and clamping plates arranged on said I surfaces having box and havingclamping edges arranged to i engage the conduits substantially at the base of'said bushings.

6. An outlet box having one or IHOIGCOII- (luit receiving bushing-stormed integral With the base and extending into the interior of the box and clamping platesarranged at the rear of the base adjacent the entrance to each bushing and constructed and arranged to engage a conduit substantially in the plane of the base of the ox. I

7. An outlet box having one or more conduit receiving sockets, clamping plates arranged adjacent said sockets, cooperating inclined bearing surfaces upon said clam ing plates and box respectively, whereby said plates may beforced to the clamping position, one of said bearing surfaces having an inclined rib and the other of said bearing a corrcspomling'ly inclined groove whereby friction between said suriavbsxvill be reduced to a minimum.

S. In an outlet box having one or more (-mulHit ri-wtciviug bushings, an inelincd sur face on the base having an inclined surface :erate with the first named of said box adjacent each of said bushings, and clamping plates'each adapted to 006 surface whereby said plates may be drawn to clamping position and a groove in one of said cooperating surfaces and a ridgein the other of said surfaces adapted to engage said groove Wl161'6 by said plate \vill'be guided to clamping po-, sition. I

9. An outlet box having one or more integral conduit receivingbushings, conduit clamping plates arranged adjacent the en trance to said bushings and knock out-disks for said bushings separate from said clamping plates, said disks having laterally ex.- tending lugs arranged tobe held, between said plates and the box to hold said disks in position oxer said bushings and adapted to be broken off in removing said disks. WlLL'IAh-l A. BONNEL'LL' Witnesses:

ll. (7. Pownm, (Hus. A. lnum. 

